Objective:To construct recombinant plasmid p EGFP-N1-IGF-Ⅰ by fusing expression of insulin-like growth factor-Ⅰ(IGF-Ⅰ)and enhanced green fluorescent protein(EGFP);to investigate accelerating effect of p EGFP-N1-IGF-Ⅰ transfection on cytoactive and early stage osteogenic differentiation of rat dental follicle cells(DFCs)in vitro. Methods:The rat dental follicle cells(r DFCs)were obtained and divided into four groups:blank group

p EGFP-N1-IGF-Ⅰ group

p EGFP-N1+liposome group and p EGFPN1-IGF-Ⅰ+liposome group. The proliferation and early stage osteogenic differentiation of DFCs were analyzed. The green fluores cence expression

MTT assay

ALP quantitative detection

Type Ⅰ collagen Col1α1 and Col1α2 gene expression analysis were used.Results:The green fluorescence expression results showed that the p EGFP-N1-IGF-Ⅰ was successfully transfected in DFCs and the transfection efficiency was higher in liposome treated group(p EGFP-N1+liposome group and p EGFP-N1-IGF-Ⅰ+liposome group)than in p EGFP-N1-IGF-Ⅰ group and blank group at 48 h. The MTT assay elucidated that the p EGFP-N1-IGF-Ⅰ may enhance the cytoactive of DFCs but the cytotoxicity of liposome may reduce the cell variability. The assay of alkaline phosphatase(ALP)activity indicated that p EGFP-N1-IGF-Ⅰ was able to increase the ALP activity. The PCR results illustrate that p EGFP-N1-IGF-Ⅰ could enhance the relative expression of Col1α1 and Col1α2. Conclusion:p EGFP-N1-IGF-Ⅰ could enhance the proliferation and early stage osteogenic differentiation of DFCs

and provide a reference for the usage of IGF-Ⅰ gene in periodontal tissue engineering.